Efficacy of Cataract Surgery With Trabecular Microbypass Stent Implantation in Combined-Mechanism Angle Closure Glaucoma Patients

Abstract

Purpose: To evaluate the effectiveness of trabecular microbypass stent (iStent) implantation in combined mechanism glaucoma (CMG).

Design: Retrospective cohort study.

Methods: We reviewed the medical charts of patients with the following scenarios: (1) primary open-angle glaucoma (POAG) undergoing phacoemulsification (PE), (2) POAG undergoing PE with iStent (POAG-PE/iStent), (3) CMG undergoing PE (CMG-PE), and (4) CMG undergoing PE with iStent (CMG-PE/iStent). CMG was defined as narrow-angle glaucoma patients whose angle had opened after iridotomy. Linear mixed-effects models were performed to determine the effect of iStent on postoperative 1-year success rate (intraocular pressure [IOP] ≤ 18 without medication), IOP, and number of medications.

Results: Data from 301 eyes were available. The number of eyes (subjects) was 61 (45) in the POAG-PE, 60 (50) in POAG-PE/iStent, 93 (76) in CMG-PE, and 87 (70) in CMG-PE/iStent group. Success criteria were achieved in 13.1% for POAG-PE, 33.3% for POAG-PE/iStent (POAG-PE vs POAG-PE/iStent B 3.01; P < .001), 37.6% for CMG-PE, and 43.7% for CMG-PE/iStent (CMG-PE vs CMG-PE/iStent B 2.25; P < .001). There was no difference in the IOP between POAG-PE and POAG-PE/iStent, and between CMG-PE and CMG-PE/iStent. The iStent significantly reduced number of medications in the POAG (B -0.70; P < .001) and CMG group (B -0.52; P < .001). Comparing the effect of iStent on POAG and CMG, the analysis showed similar iStent efficacy in terms of the success rate, IOP, and number of medications (P > .05).

Conclusions: Combined PE/iStent significantly increased success rate and reduced number of medications in CMG patients compared to PE alone. The effects of iStent were comparable between POAG and CMG groups.